I'm guessing the system gets overheating - perhaps power management is not kicking-in in Ubuntu
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Sathya♦May 16 '11 at 6:08

I suspected that too. That's why I cleaned dusts. Moreover I tried to open my laptop so that I can touch my cooler device directly and run Ubuntu. However, after the laptop was automatically shotdown, the cooler device is not that hot.
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Alex YeungMay 16 '11 at 6:22

4 Answers
4

Should be able to boot into Dell's Hardware Diagnostics by hitting F12 at the bios screen.
From there you can run all sorts of hardware tests. If you spits out an error with one of the tests and your laptop is still under warrenty, should be able to call Dell and get it replaced.

Thanks for your answer. I will try tonight because my laptop is at home.
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Alex YeungMay 16 '11 at 6:19

@Nixphoe: I run the test yesterday. But I cannot complete the test because my computer is auto shutdown. I tried the test for few times.
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Alex YeungMay 17 '11 at 23:33

I would put my money down that it's a hardware issue. Grab your Dell Service tag. Should be able to check here to find out if your warrenty is still good. Call Dell if it still is and let them know what the issue is and what you've already done. support.dell.com/support/topics/global.aspx/support/…
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NixphoeMay 17 '11 at 23:58

I don't believe that is a hardware issue. Because it works fine under Windows 7.
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Alex YeungMay 18 '11 at 4:05

I have a feeling that it is more of a fluke that it is working under Windows 7. If it is rebooting when only running a hardware check, Dell will tell you that it is hardware. I've been through that a few times with them on workstations.
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NixphoeMay 18 '11 at 14:52

Ubuntu 11.04 Desktop is still BETAWARE. Wait a wee or two, & the debugged version should be released.

Very few of the Ubuntu derivatives dare use Ubuntu 11.04 yet. Pinguy has ... but I've yet to install it. Generally I use Super OS, which tries to prompt me to 'upgrade' to the buggy 11.04. I did try the UNITY stuff on 10.10 - not impressed. Also COMPRIZ (?) and other GPU demanding stuff won't work with my notebook's Intel I3 CPU.